1. Field of the Invention
The present invention relates to an adhesive skin patch sheet that is applied, for instance, onto the skin surface.
2. Description of the Related Art
Known adhesive skin patch sheets applied onto the skin surface include, for instance, adhesive skin patches such as anti-inflammatory analgesic adhesive patches or the like for transdermal administration of a medicinal agent with a view to, for instance, treating a condition. Such adhesive skin patch sheets comprise ordinarily a flexible support, for following the skin contour; a pressure-sensitive adhesive layer containing the medicinal agent, formed on the support; and a release sheet for protecting the pressure-sensitive adhesive layer until use of the adhesive skin patch sheet.
To use the adhesive skin patch sheet, the release sheet is peeled off and the pressure-sensitive adhesive layer exposed thereby is applied onto the skin surface. However, the support is flexible and thus difficult to hold in the hand. As a result, the adhesive skin patch sheets bends when attempting to apply the whole pressure-sensitive adhesive layer in one go after peeling off the entire release sheet, which gives rise to problems such as adhesion between pressure-sensitive adhesive layers, and wrinkling of the adhesive skin patch sheet applied onto the skin surface.
Adhesive skin patch sheets have been proposed in which straight-line or wavy cuts are made on the release sheet, dividing thereby the release sheet in two, with a view to enhancing the handleability of the adhesive skin patch sheet (Japanese Utility Model Registration Nos. 2596722, 2597846, Japanese Utility Model Application Laid-open No. 58-124123). To use such adhesive skin patch sheets, one of the release sheets (first release sheet) is peeled off and the exposed half pressure-sensitive adhesive layer is applied onto the skin surface, whereafter the adhesive skin patch sheet is bent, and the other release sheet (second release sheet) is gradually peeled, from the inner end thereof toward the outer end, at the same time that the exposed pressure-sensitive adhesive surface is gradually applied onto the skin surface. Such adhesive skin patch sheets are easier to handle than those in which the whole pressure-sensitive adhesive layer is applied in one go after having peeled off the entire release sheet.
Adhesive skin patch sheets where the release sheet is cut with a straight line cut, however, are problematic in that the second release sheet lacks a portion that can be picked with the fingers when peeling the second release sheet, from the inner end thereof to the outer end, after having applied half of the pressure-sensitive adhesive layer onto the skin surface, so that the second release sheet is difficult to peel off.
Adhesive skin patch sheets where the release sheet is cut with a wavy cut, on the other hand, are advantageous in that the second release sheet has a portion that can be picked with the fingers when peeling off the second release sheet, from the inner end thereof to the outer end, after having applied half of the pressure-sensitive adhesive layer onto the skin surface, so that the second release sheet is easy to peel off. Such adhesive skin patch sheets, however, are often prone to wrinkle during applying of the second half of the adhesive skin patch sheet. This wrinkling is believed to be caused by the wavy end edge of the second release sheet.